Although there’s no reason to do this, but some of you might have problem with apps not running well in multi-core environment or maybe looking to save some power (although disabling cores on sandy-bridge CPUs won’t save much power), I’ve written this simple tutorial to disable CPU cores in Linux.
I have i7 2630QM process which has 4 physical cores and 4 logical cores. I’ll show you how to make it act like a dual core machine instead.
This method is dynamic and doesn’t require a reboot. You can just open a terminal and try this out:
sudo sh -c "echo 0 > /sys/devices/system/cpu7/online" sudo sh -c "echo 0 > /sys/devices/system/cpu6/online"
Repeat the above steps for cpu2 to cpu7 and it’ll leave you with cpu0 and cpu1 active which is essentially what we’re trying to achieve.
This method will make the linux boot with 2 cores which might make kernel more optimized for dual core environment than the method above.
- Add maxcpus=2 to GRUB command line by doing the following:
gksu gedit /etc/default/grub
and change it to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash maxcpus=2"
- Then run:
When you reboot, linux will run on 2 cores.